#include<iostream>
using namespace std;
int main(){
	int n;
	int a[17][17];
	while (cin >> n){
		for (int i = 0; i < n; i++){
			a[i][0] = 1;
		}
		for (int j = 0; j < n; j++){
			a[0][j] = 1;
		}
		for (int i = 1; i < n; i++){
			for (int j = 1; j < n; j++){
				a[i][j] = a[i-1][j]+a[i][j-1];
			}
		}
		cout << a[n-1][n-1] << endl;
	}
	return 0;
}
